Slide valve of steam pumps



' K. NAKAO SLIDE VALVE OF STEAM PUMPS Filed A rgl a, 1921- 5Sheets-Sheet 1 4-5- 4.4. 5,"- 4i- I /4 1 /4 #0 /I 6 1' 40/11 4 1,5 4, 3+f f 50 t 3 x I I was; 35

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' K. NAKAO SLIDE VALVE OF STEAM PUMPS Filed April 9, 1921 5 Sheets-Sheet5 l'lgll V////////I//////////////%A ///////////////////A--//////////4"'//////AZ WW K. NAKAO SLIDE VALVE 0F STEAM PUMPS Filed April9, 1921 T Illllll 5 Sheets-Shet 5 Patented Jan. 27, 1925.

UNITED STATES PATENT OFFICE.

KINZABURO NAKAO, F TOKYO, JAPAN.

SLIDE VALVE OF STEAM PUMPS.

Application filed April 9,

certain new and useful Improvements in Slide Valves of Steam Pumps, ofwhich the following is a specification.

The invention is an improvement in piston valves for steam engines, suchas steam pump engines.

Heretofore, it has been customary to operate such valves by the fresh orlive steam introduced into the steam chest. This has serious drawbacks,particularly the loss of heat energy used in driving the valve back andforth, and also complication in the mechanism.

The valve mechanism of the present invvention comprises a valve operatedby the exhaust steam from the steam-cylinder of the engine subject tosaid valve, whereby the above-mentioned loss of heat energy is avoided.The invention also makes possible a simple form of construction, easy toadjust and repair.

More specifically, the invention comprises a valve mechanism wherein thevalve member is driven back and forth longitudinally by the exhauststeam pressure from the steam-cylinder controlled by the valvemechanism, and is oscillated mechanically from the piston rod. I

The preferred embodiment will now be described.

In the accompanying drawings, illustrating a preferred embodiment of theinvention Fig. 1 is a vertical longitudinal section through the valveand steam chest, taken on the line 11 of Fig. 2;

Fig. 2 is a central transverse section on the line 2-2 of Fig. 1;

Fig. 3 is a longitudinal section on the line 3-3 of Fig. 2, this viewand Fig. 1 showing the valve member in a. central position Fig. 4C is aside view of the liner;

Fig. 5 is an end elevation, looking at the left hand end of Fig. 4;

Fig. 6 is a. side elevation of the valve member or piston;

Fig. 7 is an end elevation, looking at the left end of Fig. 6';

1921. Serial No. 460,027.

F ig. 8 is a longitudinal section through the liner and valve membertaken in the same plane as Fig. 3, showing the valve member in itsright-hand position;

Fig. 9 is a similar view showing the valve-member in its left-handposition;

Fig. 10, is a transverse section on the line 10-1O of Fig. 9;

Fig. llcorrespondsto Fig. 9,except that the valve member has been turnedrelatively to the liner (for convenience the plane of the sectionremains fixed as to the valve member and has been shifted as to theliner) Fig. 12 is a view corresponding to Fig. 11, except that the valvemember has been moved to the right (Fig. 12 differing from Fig. 8 in thedifferent angular relation between the valve and liner) Fig. 13 is atransverse section on the line 13-13 of Fig. 12;

Fig. 14 is a horizontal section on the line 14[llof Fig. 2, showing moreparticularly the starting valve;

Fig. 15 is a detail View of the starting valve member; and

Fig. 16 is an elevation of a steam-pump embodying the invention.

The steam-chest is marked a, and the steam-cylinder (Fig. 16) b. Thesteamchest has a live steam chamber and an exhaust chamber 13 atopposite sides. In the part of the chest which is applied to thesteam-cylinder are passages 11 and 12, at opposite sides of the exhaustchamber 13.

The liner 6 is fitted tightly in the steamchest, and is provided at oneend with three parallel circumferentially elongated ports 1,. 2, and 3,open, respectively, to the passages 11, 13 and 12. In the opposite sideof the liner are two ports l: and 5, which are open to the live steamchamber 50 and which are spaced from each other at opposite sides of thetransverse central plane and are also offset or staggered with respectto each other circumferentially of the liner. In the opposite endportions of the liner, near the top, are longitudinal slots, or endports, 7 and 8 in circumferentially offset or staggered relation. Atransversely elongated port 6' in the central upper part of the liner isin communication withthe exhaust steam chamber 13, through. a port 43 inthe latter, a passage 41 leading from the port 43, a passage 44 leadingat an angle from the passage 41, and a port 6 at the end of the passage44 open to the port 6. In the bottom of the liner, in longitudinallyspaced and circumferentially offset relation, are escape ports 9 and 10,in communication with passages 33 and 32in the wall of the chest, theselast passages either being open to atmosphere or being connected withthe condenser (not shown).

The sliding or piston valve 7 is mounted for longitudinal reciprocatoryand rotary oscillatory movement in the liner. In one end it has a squaresocket having sliding but non-rotary engagement with the square end of arock-shaft 52. The valve member has closed end walls and is dividedinteriorly by suitable walls 31 into three noncommunicating chambers 60,61. 62.

In one side of the valve member are four parallel, circumferentiallyelongated ports 20, 21,22, 23, to cooperate with the liner ports 1, 2,3; and in the opposite sides are two ports 24, 25, arranged inlongitudinal alinement, at opposite ends of the transverse centralplane, to cooperate with the longitudinally spaced and circumferentiallyoffset ports 4 and 5 in the liner. The ports 20 and 24 are incommunuication with each other through the right-hand end chamber 62.The ports 23 and 25 similarly communicate with each other through theleft-hand chamber while the ports 21 and 22 constitute the opening tothe central chamber 61. In the top of the valve member, not extendingthrough its wall, is a longitudinal groove 26, which has continuouscommunication with the port 6 and is adapted to communicate alternatelywith the circumferentially otlset liner slots 7 and 8. Toward oppositeends of the piston valve member, and at opposite sides thereof, arecircumferentially extending grooves 27 and 28 reaching from the bot-tomto near the top, and having at the bottom longitudinal, alinedextensions 29 and 30 adapted to communicate alternately, respectively,with the liner ports 9. 10. The upper portions of the grooves 27, 28,,are adapted to cooperate with the liner slots 7, 8. V

The rock-shaft 52has a crank 53, which is pivotally connected with alongitudinally movable rod 54 carrying spaced, adjustable nut collars56, 57 adapted to be encountered alternately by a tappet fork 55 on thepiston rod 58 of the engine.

The operation of the parts above identified will now be described.Assume the pision valve member to be in the position of Fig. 8 and thepiston of the steam cylinder 1) to be at the upper end of the stroke.The longitudinal groove 26 in the valve member now registers with thelongitudinal liner slot 7, admitting exhaust steam from the port 6through the groove 26 and slot 7 to the space at the right-hand of theiston valve member. At the same time, t e opposite end of the pistonvalve chamber is placed in communication with the atmosphere or the lowcondenser pressure through the liner slot 8, the groove 28, itsextension 30 and the liner port 10. The result is to drive the valvemember to the left, because the pressure of the exhaust steam is higherthan that of the condenser or of the atmosphere, and suflicient to movethe valve. The valve member will then assume the position of Fi 9. Whilethe valve was moving toward the eft, its port 24 opened to the linerport 5, while the ports 20, 21, 22 opened to the liner ports 1, 2, 3,respectively. Consequently, in the position of Fig. 9, the lower end ofthe steam-cylinder is placed in communication with the exhaust throughthe ports 3 and 22, the chamber 61 and the ports 21 and 2. At the sametime the upper end of the steamcylinder is placed in communication withthe live steam through the ports 5 and 24, the chamber 62 and the ports20 and 1. The downward stroke of the engine piston therefore takesplace. At an appropriate point in such downward stroke, the tappet 55comes in contact with the collar 57 depressing the same and the rod 54and rocking the arm 53 and the shaft 52, which gives the valve member apartial turn in one direction, eventually bringing the valve member intothe position of Fig. 11. During the turning movement of the valve, theport 24 is closed from the port 5, so that the steam ex ands in thesteam-cylinder during the comp etion of the power piston stroke. At orbefore the time the piston has finished its downward stroke the valvehas taken the position shown in Fig. 11. This turning movement carriesthe groove 26 out of register with the slot 7 and into register with theslot 8; and the same operation causes the oove 27 and its extension 29to place the slot 7 in communication with the port 9 (to atmosphere orcondenser) by way of passages 27, 29, 9 and 33, and to shift the groove28 and its extension 30 so that the slot 8 no longer is in communicationwith the port 10. The exhaust steam from the port 6 is thereforeadmitted to the left hand end of the valve, and causes the same to bedriven to the right, moving it to the position of Fig. 12. This causesthe port 25 to open to the port 4, and the ports 21, 22, and 23 to open,respectively, to the ports 1, 2, and 3, while the port 20 is carried outof communication with the port 1.

Live steam will now pass by way of ports 4, 25, and chamber 60, andports 23 and 3 to the lower end of the steam cylinder, while the upperend of said cylinder is open to exhaust by way of ports 1, 21, chamber61, and ports 22 and 2. Consequently the piston ofithegsteam cylinderwill ibedriven upward.

At, azcertain point'in thisstrokeithe.tappet the groove 27, 29 no longerconnects the slot 7 with the port 9. The movement of the valve to theleft then takes place, and the cycle of operations is repeated.

When starting, there is no exhaust steam in the. valve chest to operatethe valve, and at this time the valve must be operated by live steam.For this purpose a manually operated starting valve, an illustrativeform of which is shown in Figs. 14 and 15, is employed.

The channel 41 hereinbefore referred to is continued so as tocommunicate with the live-steam chamber 50, throu 'h a port 12-. A valverod 40 is placed slidably and rotatably in this passage, having ahandwheel 40 at its outer end and a screw portion 40 to cooperate with acorresponding fixed nut part. The part of the rod in the passagecomprises fluted guide portions 40 and a cylindrical obturating portion40. The last, in the normal operation of the valve mechanism, isdisposed between the entrance to the channel 44 and the live steam port42, preventing communication with the port 6. By turning the wheel 40".however, the plug portion 40 can be carried to the other side of thepassage 44, so that live steam is admitted to the port 6, to operate thevalve. After a few strokes of the piston under this condition, thestarting valve may be restored to its normal position, seen in Fig. 141,after which the valve will be operated by the newly-produced exhauststeam.

What I claim as new is:

1. In a steam-engine, a steam-chest having a live-steam inlet chamber,an exhauststeam outlet chamber and a piston-valve chamber, areciprocatory and. oscillatory piston-valve in said piston-valvechamber, with means for oscillating said valve mechanically, thepiston-valve chamber having a wall or liner containing at one side agroup of three ports to the opposite ends of the steam-cylinder of theengine and to said exhaust-steam chamber respectively and at anotherside two live-steam ports opening from said live-steam chamber, thepiston valve comprising three parts or chambers adapted to cooperatewith the said-ports in the liner to admit liveistefam to control thepassage of steam to and from the steam-cylinder, the liner andvalve-further provided with ports andpassages for alternately placingthe endsof the valve chamber in communication with the. saidexhaust-stea1n outlet; chamber as the valve is mechanically oscillated,so as to cause the valve to be reciprocated by exhaust steam from saidoutlet chamber.

2. The subject-matter of claim 1, further characterized by the provisionof a channel between the said live-steam and exhauststeam chambers, anda valve in said channel movable at will to permit at starting the flowof live steam to the passages for reciprocating the valve.

3. A steam engine valve mechanism comprising a wall or liner having atone side a group of three ports to the opposite ends of the steamcylinder and to the exhaust, re spectively, and at another side twolivesteam ports, and a reciprocatory and oscillatory piston valvedivided into three parts or chambers and having at one side ports in thedifferent chambers to cooperate with said group of three ports in theliner and at the other side two ports in the end chambers in staggeredrelation to the livesteam ports, said liner being provided withlongitudinal end slot ports, an exhauststeam port, and escapeports, andthe valve having a groove arranged to register alternately byoscillation with said end slot ports while communicating with saidexhaust-steam port, and being provided with other grooves arranged toconnect alternately by oscillation the said end slot ports with theescape ports.

4. A steam engine valve mechanism, comprising a wall or liner having atone side a group of three ports to the opposite ends of the steamcylinder and to the exhaust, respectively, and at another side twolivesteam ports, and a reciprocatory and oscillatory piston valvedivided into three parts or chambers and having at one side ports in thedifferent chambers to cooperate with said group of three ports in theliner and at the other side two ports in the end chambers in staggeredrelation to the live-steam ports, said liner being provided withlongitudinal end slots, an exhaust-steam port, and escape ports, and thevalve having a longitudinal groove arranged to register alternately byoscillation with said end slots while communicating at the center withsaid exhaust-steam port, and being provided wiith other angular groovesarranged to connect alternately by oscillation the said end slots withthe escape ports.

5. In a steam-engine, a valve mechanism comprising a wall or linerhaving longitudinal end slot norts, a central exhaust-steam port, andescape ports, a reciprocatory and oscillatory piston valve in the linerhaving a groove arranged to register alternately by oscillation withsaid end slot ports while communicating with said exhaust-steam port,said valve being provided with other grooves arranged to connectalternately by oscillation the said endslot ports with the escape ports,and means for oscillating the valve from the piston rod of the engineWithout interfering with its reciprocation by the exhaust-steampressure.

In testimony whereof I aflix my signature.

KINZABURO NAKAO.

